1. Field of the Invention
The present invention relates generally to read head portions of magnetic heads for hard disk drives, and more particularly to lead overlaid read heads wherein the electrical leads and second magnetic shield are combined.
2. Description of the Prior Art
Increasing the performance of hard disk drives may be achieved by increasing the areal data storage density of the magnetic hard disk. This can be accomplished by reducing the written data track width, such that more tracks per inch can be written on the disk. To read data from a disk with a reduced track width, it is necessary to develop read heads with a sufficiently narrow read width, such that the narrow data tracks can be accurately read, and unwanted magnetic field interference from adjacent data tracks is substantially eliminated when reading a narrow data track.
The standard prior art read head elements include a plurality of thin film layers that are deposited and fabricated to produce a GMR read head, as is known to those skilled in the art. Significantly, where the width of the thin film layers that comprise the GMR read head sensor are reduced below certain values, the magnetic properties of the layers are substantially compromised. To overcome this problem, GMR read heads have been developed in which the thin film layers have an ample width and the electrical leads are overlaid on top of portions of the thin film layers. This lead overlaid configuration has the effect of creating an active read head sensor region having a read width that is less than the entire width of the deposited sensor layers, such that the magnetic properties of the thin film layers can be preserved. Thus, in the lead overlaid GMR read heads of the prior art, the active magnetic layer portions of the sensor exist between the inner ends of the electrical leads.
Increases in the areal data storage density of magnetic disks are also achieved by increasing the number of bits per inch on the data tracks of the disk, and this is accomplished by reducing the in-track size of the data bits. To read such reduced size data bits, it is necessary to reduce the read gap of the read sensor, where the read gap is defined as the distance between the magnetic shields that are fabricated beneath and above the sensor layers.
To improve the performance characteristics of such lead overlaid read heads, it is therefore desirable to decrease the read width between the inner ends of the overlaid leads and to decrease the read gap between the magnetic shields. The present invention addresses these issues.